On this level you'll use the blasting station to shoot enemies away from Murray, who needs to get up to the key. This is mainly about playing through over and over to memorize where the enemies jump out. If you shoot Murray you'll kill him and have to start over. Murray also dies if you shoot the explosive barrels next to him. The good news is he has all the lucky charms you do, and when you die enough you'll start getting some when you restart. Take your time so you can avoid the barrels, especially when they try to trick you with a garage full of them and no enemies. Protect him the entire way and the key is yours.